Video RAM is important. You'll be happy to know that 6.5 has some enhanced (speed improvements) over 6.01. Especially using mental ray. You can up the Systems RAM io 1gb which might help things but hang in there & see how the 512 works out. The video R is low, ? / There are no video compatibility checks for 6.5, video cards on a MAC yet. Is it NVIDIA or ATI. Good Luck with it!!